Swing-arm integrated exhaust silencer

ABSTRACT

A Swing-arm Integrated Exhaust Silencer is disclosed. The Silencer is designed to be incorporated within the conventional swingarm of a motorcycle. One version has a removable silencer cartridge that installs within the inner chamber of the motorcycle&#39;s swingarm. Another version allows the exhaust stream to be diverted from the conventional silencer and into the inner chamber of the swingarm. In either version, the swingarm has plurality of apertures formed in it to allow for exhaust gas exit. The invention includes an adapter device that splits the exhaust gas exiting the engine and redirects it into the swingarm-integrated silencer. The exhaust adapter device is somewhat flexible to allow for movement between the swingarm, the engine, and the conventional silencer&#39;s exhaust pipe.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to motorcycle engine exhaust systems and, more specifically, to a Swing-arm Integrated Exhaust Silencer.

2. Description of Related Art

Motorcycles are available in a variety of shapes, sizes and configured for different environments. The portion of the conventional motorcycle that is the subject of this invention is related to the engine exhaust and sound suppression system. Each type or class of motorcycle has an exhaust and noise suppression system specific to the use pattern of that type or class. For example, a “street” cycle exhaust system design will emphasize aesthetic physical appearance as well as richness of sound. In some of these “custom” street bikes, extensive research is used to arrive at a particular sound quality and engine performance traits. In contrast, designs for off-road motorcycles place almost no value on the aesthetics or sound qualities. The most important traits for the exhaust systems of these motorcycles are minimization of the engine exhaust noise, minimizing the weight of the system and maximization of the rear wheel suspension travel (and engine performance, of course). FIG. 1 depicts the conventional arrangement for these types of cycles.

FIG. 1 is a perspective view of a conventional motorcycle 10. The engine 12 is mounted to the cycle frame 14 in generally the center of the cycle 10. The engine exhaust exits the engine into the exhaust pipe 18 in a generally upward direction. The exhaust pipe 18 transitions into the exhaust silencer 16. The exhaust pipe 18 and silencer 16 are typically located just underneath the rider's seat 17 so that the rear wheel 20 travel (up and down) is maximized.

The rear wheel 20 and related suspension involves one major component on the typical motorcycle 10—the swing arm 24. The swing arm 24 attaches to the cycle 10 frame 14 at the pivot mount 26 (i.e. at the proximal end of the swing arm). The rear wheel 20 (specifically the rear hub assembly 22) is attached to the distal end of the swing arm 24. Although not depicted here, there is a shock absorber/strut interconnecting the swing arm 24 and the frame 14 that provides the shock dampening support for the swing arm 24. FIG. 2 provides additional detail regarding the typical cycle.

FIG. 2 is a partially cutaway perspective view of the motorcycle of FIG. 1 depicting the critical components of the cycle rear suspension and exhaust system. The exhaust system connects to the engine at the inlet port 28. As discussed above, the silencer 16 is positioned just beneath the seat (see FIG. 1) in order to maximize the amount of travel 33 that the rear wheel 20 can travel before the suspension will stop travel to prevent contact with the silencer 16. In other versions, the silencer 16 is positioned to the side of the seat. The rear wheel 20 rotatably attaches to the distal end of the swing arm 24 at the rear axle 30. The swing arm 24 pivots around the pivot mount 26 in direction 32, which is essentially up and down at the rear axle 30.

There are at least two problems with this prior design: its weight and its lack of performance. If a supplemental silencer could be installed in the system without requiring additional space, undesirable noise levels could be reduced. Furthermore, if the silencer's functionality could be incorporated in another structural element, it would be expected to reduce the overall weight of the cycle, thereby improving cycle performance.

Furthermore, the off-road motorcycling has substantially converted to 4-stroke engines, and away from 2-stroke engines. The 4-stroke engines have proven to be quite a bit louder than the 2-stroke engines, to the point where additional exhaust noise suppression is required in order to avoid environmental problems.

SUMMARY OF THE INVENTION

In light of the aforementioned problems associated with the prior devices and systems, it is an object of the present invention to provide a Swing-arm Integrated Exhaust Silencer. The Silencer should be incorporated within the conventional swingarm of a motorcycle. One version should have a removable silencer cartridge that installs within the inner chamber of the motorcycle's swingarm. Another version should simply allow the exhaust stream to be diverted from the conventional silencer and into the inner chamber of the swingarm. In either version, the swingarm should have a plurality of apertures formed in it to allow for exhaust gas exit. The invention should include an adapter device that splits the exhaust gas exiting the engine and redirects it into the swingarm-integrated silencer. The exhaust adapter device should be somewhat flexible to allow for movement between the swingarm, the engine, and the conventional silencer's exhaust pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings, of which:

FIG. 1 is a perspective view of a conventional motorcycle;

FIG. 2 is a partially cutaway perspective view of the motorcycle of FIG. 1;

FIG. 3 is a partially cutaway perspective view of the motorcycle of FIGS. 1 and 2 having a preferred embodiment of the present invention installed thereon;

FIG. 4 is a perspective view of the assembly of FIG. 3;

FIG. 5 is a cutaway top view of the swingarm assembly of FIGS. 3 and 4; and

FIG. 6 is a cutaway top view of an alternate embodiment of the swingarm assembly of FIGS. 3 and 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein specifically to provide a Swing-arm Integrated Exhaust Silencer.

The present invention can best be understood by initial consideration of FIG. 3. FIG. 3 is a partially cutaway perspective view of the motorcycle of FIGS. 1 and 2 having a preferred embodiment of the present invention installed thereon. The invention is a swingarm-integrated exhaust silencer assembly 40. The assembly 40 seeks to divert the exhaust gases from the engine so that instead of entering the exhaust pipe 18 and silencer 16, they travel through an integral silencer element 42 that is actually located within the hollow inner chamber of swingarm 44. The adapter element 46 is inserted between the conventional exhaust pipe 18 and the engine exhaust, and further provides a branch to the integral silencer element 42. In other (non-depicted) versions, the adapter element 46 will provide only a single outlet, namely to the integral silencer element 42. In this non-depicted version, the conventional exhaust pipe 18 and silencer 16 can be completely removed. FIG. 4 provides additional detail regarding this embodiment of the present invention.

FIG. 4 is a perspective view of the assembly 40 of FIG. 3. The assembly 40 comprises an adapter element 46, which in this version is defined by an inlet port 48 for connection to the engine exhaust port. The adapter element 46 is further defined by a legacy outlet port 50, for attaching to the exhaust pipe inlet port (see FIG. 2). The adapter further has a swingarm adapter portion 52 for interconnection with the swingarm exhaust pipe 54.

The swingarm adapter portion 52 is preferably made from flexible material so that the swingarm 44 will not be restricted in its movement as it absorbs shocks to the suspension. The swingarm exhaust pipe 54 penetrates the housing 45 of the swingarm 44 and attaches to the integral silencer element 42 that is located therewithin.

As discussed previously, it is possible that the adapter element 46 has only an inlet port 48 and an outlet port at the end of the adapter portion 52. This would serve to completely remove the OEM exhaust system from the exhaust flow path and redirect that flow to the integrated silencer 42.

FIG. 5 is a cutaway top view of the swingarm 44 of the assembly of FIGS. 3 and 4. The swingarm 44 has a pivot mount 26 for pivotal attachment to the frame of the cycle. The swingarm exhaust pipe 54 is an angled section having an upwardly-directed inlet port 58 that protrudes from a central section of the cross-strut 53 at one end (for connection to the flexible swingarm adapter portion 52), and is connected to the integral silencer element 42 at the other end. The cross-strut 53 is a hollow structural member that interconnects the right and left swingarm housings 45.

The swingarm 44 has a housing 45 that provides the same structural rigidity as the conventional swingarm, but further defines an internal chamber 56 formed therein. The swingarm exhaust pipe 54 enters through the top surface of the housing 45, and the integral silencer 42 is positioned within the internal chamber 56

The rear axle 30 extends through the distal end of the swingarm 44 for rotatably mounting the rear wheel thereto. In order to allow for the exit of the hot combustion gases, the swingarm 44 will be provided with one or more penetrations or apertures 57 formed through the wall of the housing 45. There are also a plurality of exhaust apertures 57 formed in the bottom surface of the housing 45. Allowing the exhaust gases to exit through the bottom of the housing 45 provides a safe location for the hot gases, while also capitalizing on the sound-dampening effect of being directed towards the ground. The actual location and sizing of the apertures 57 is determined by optimization of the engine performance.

In another version of the present invention, as depicted in FIG. 6, the swingarm 44 is simply a hollow housing 45 (i.e. absent the silencer element of the design of FIG. 5). By directing exhaust gas flow through the inlet port 58, through the cross-strut 55 and into the housing 45, superior sound dampening will be achieved over the conventional silencer/exhaust system. As with the version shown in FIG. 5, there are a plurality of exhaust apertures 57 dispersed along the bottom wall 59 of the housing 45 to direct the exhaust gases towards the ground.

Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein. 

1. A suspension swingarm for motor vehicles, comprising: a housing defined by a proximal end and a distal end; an internal chamber formed by said housing; and an inlet port in fluid communication with said internal chamber, said inlet port extending from said housing.
 2. The swingarm of claim 1, wherein said motor vehicles include an internal combustion engine mounted thereto and further defined by an exhaust port, said swingarm comprising: a swingarm exhaust pipe configured to interconnect the engine exhaust port and said inlet port.
 3. The swingarm of claim 2, wherein said inlet port extends upwardly from a cross-strut interconnecting right and left swingarm members.
 4. The swingarm of claim 3, further comprising a pivot mount associated with a proximal end of said swingarm and a rear axle associated with a distal end of said swingarm, said pivot mount cooperating with a frame of said motor vehicle to allow for rotational movement between said swingarm and the frame about said pivot mount.
 5. The swingarm of claim 4, wherein said housing is further defined by a plurality of apertures formed therein to allow for fluid communication between said internal chamber and the exterior of said housing.
 6. A method for changing the path of exhaust gases exiting an external combustion engine of a motor vehicle, the motor vehicle comprising at least one exhaust pipe extending from the engine exhaust port, a silencer element extending from the exhaust pipe, and at least one swingarm attached between the motor vehicle frame and a motor vehicle rear wheel, the method comprising the steps of: disconnecting said exhaust pipe from said engine exhaust port; replacing said swingarm with a replacement swingarm defined by: a housing defined by a proximal end and a distal end; an internal chamber formed by said housing; and an inlet port in fluid communication with said internal chamber, said inlet port extending from said housing; and interconnecting said engine exhaust port with said inlet port.
 7. The method of claim 6, wherein said replacing step comprises inserting an adapter element between said engine exhaust port and said inlet port.
 8. The method of claim 6, wherein said replacing step comprises replacing said swingarm with a replacement swingarm, wherein said replacement swingarm is further defined by a swingarm exhaust pipe interconnecting said adapter element and said inlet port.
 9. The method of claim 6, wherein said replacing step comprises inserting an adapter element between said engine exhaust port and said inlet port, wherein said adapter element further comprises a swingarm adapter portion connected to said swingarm exhaust pipe.
 10. The method of claim 9, wherein said replacing step comprises inserting an adapter element between said engine exhaust port and said inlet port, wherein said adapter element further comprises a flexible tubular swingarm adapter portion connected to said swingarm exhaust pipe.
 11. The method of claim 6, wherein said replacing step comprises inserting an adapter element between said engine exhaust port and said inlet port, wherein said adapter element further comprises legacy outlet port separate from a swingarm adapter portion connected to said swingarm exhaust pipe, said swingarm adapter portion attached to said inlet port and said legacy outlet port attached to said exhaust pipe.
 12. The method of claim 9, wherein said replacing step comprises inserting an adapter element between said engine exhaust port and said inlet port, wherein said adapter element further comprises a flexible tubular swingarm adapter portion connected to said swingarm exhaust pipe.
 13. A motorcycle exhaust system, comprising: a swingarm pivotally attachable to a motorcycle frame and to which a rear wheel is rotatably attachable, said swingarm defined by a housing having by a proximal end for said pivotal attachment and a distal end for said rotatable attachment; an internal chamber formed by said housing; and an internal silencer element located within said internal chamber.
 14. The system of claim 13, wherein said motorcycle includes an internal combustion engine mounted to the frame and further defined by an exhaust port, said swingarm comprising: a swingarm exhaust pipe configured to interconnect the engine exhaust port and said internal silencer element.
 15. The system of claim 13, further comprising a pivot mount associated with said proximal end of said swingarm and a rear axle associated with said distal end of said swingarm, said pivot mount cooperating with a frame of said motor vehicle to allow for rotational movement between said swingarm and the frame about said pivot mount.
 16. The system of claim 14, further comprising an adapter element interconnecting said engine exhaust port and said internal silencer.
 17. The system of claim 15, wherein said housing is further defined by a plurality of apertures formed therein to allow for fluid communication between said internal chamber and the exterior of said housing.
 18. The system of claim 16, wherein said adapter element interconnects said internal silencer element as well as an exhaust pipe leading to a second silencer element external to said housing.
 19. The swingarm of claim 1, further comprising an internal silencer element located within said internal chamber, said internal silencer element in fluid communication with said inlet port.
 20. The method of claim 6, wherein said replacement swingarm of said replacement step further comprises an internal silencer element located within said internal housing, said internal silencer element in fluid communication with said inlet port. 